A fly ash high-temperature salt separation detoxification utilization system and method based on an electromagnetic heating rotary kiln

Abstract

The application discloses a fly ash high-temperature salt separation and detoxification utilization system and method based on an electromagnetic heating rotary kiln, relates to the field of hazardous waste treatment, and provides a fly ash high-temperature salt separation and detoxification utilization system and method based on an electromagnetic heating rotary kiln, which heats steel balls and a kiln body through electromagnetic induction, realizes accurate temperature control disposal of fly ash under high-temperature conditions, and innovatively combines high-temperature filtration and quenching crystallization processes to realize efficient separation of gaseous chlorine salt and solid ash under the condition of no water washing. The method can realize complete thermal decomposition and regeneration inhibition of dioxin under the condition of 1000-1100 DEG C, realizes long-term stabilization of heavy metals through lattice solidification and physical wrapping, and obtains detoxification products with building material utilization value and salts with resource utilization value.

Description

Technical Field

[0001] This invention relates to the field of hazardous waste treatment technology, specifically to a system and method for high-temperature desalination and detoxification of fly ash based on an electromagnetically heated rotary kiln. Background Technology

[0002] With the acceleration of urbanization, municipal solid waste incineration for power generation has become the mainstream waste treatment method. However, the incineration process generates fly ash, which accounts for approximately 3%-5% of the incinerated waste. Fly ash is enriched with high concentrations of soluble chlorides, heavy metals, and highly toxic dioxins, and is listed in the National Hazardous Waste List (HW18). Improper disposal not only occupies a large amount of land resources but also causes serious pollution to soil and groundwater. Currently, the main technologies for the resource-based treatment of fly ash include water washing and desalination-cement kiln co-processing and high-temperature sintering / melting. Among these, high-temperature treatment has become a key focus of industry development due to its ability to completely decompose dioxins, solidify heavy metals, and reduce volume. However, existing high-temperature treatment technologies still have many shortcomings in terms of energy consumption control, process complexity, and secondary pollution prevention.

[0003] Against this backdrop, existing technologies, such as the Chinese invention patent "Novel Rotary Kiln Melting Method for Full Resource Recovery and Utilization of Fly Ash and Ultra-Clean Emission of Tail Gas" (CN108480360A), propose a method for high-temperature melting of fly ash using a gas-fired rotary kiln, followed by the recovery of heavy metals and soluble salts through a subsequent acid washing system. While this method achieves the resource utilization of fly ash, it suffers from the following significant drawbacks: First, the use of natural gas as a heat source results in relatively low thermal efficiency, and the combustion generates a large amount of flue gas, increasing the tail gas treatment load and carbon emissions. Second, it relies on a complex wet acid washing process to extract salts and heavy metals, which is not only lengthy but also inevitably generates large amounts of wastewater containing salt and heavy metals, increasing wastewater treatment costs and environmental risks. Another existing technology, such as the Chinese invention patent application "Method and Equipment for Preparing Water-Washed Fly Ash Hollow Microspheres Based on Electromagnetic Kiln Sintering" (CN120965367A), although attempting to introduce electromagnetic heating technology to reduce energy consumption, its core process route is still based on "water-washed fly ash." Before entering the electromagnetic kiln, fly ash must undergo a series of cumbersome pretreatment processes, including washing, grinding, batching, aging, and spray molding. This means that the method still relies on the "washing process" and faces the challenge of treating high-chlorine wastewater. Furthermore, the process aims to prepare hollow microspheres, which requires extremely high precision in raw material ratios and molding control. It is difficult to adapt to fly ash from raw waste incineration with large compositional fluctuations and cannot directly achieve gas-phase salt separation.

[0004] Furthermore, chloride scaling and corrosion are key challenges in the high-temperature treatment of fly ash. In traditional processes, gaseous salts in high-temperature flue gas are prone to scaling and clogging on the heat exchanger surface during cooling, particularly when passing through the "sticking zone" (600~800℃), making long-term stable system operation difficult. Existing wet scrubbing or conventional dry dust removal technologies often struggle to simultaneously achieve efficient heat recovery and the graded collection of high-purity salts. In electromagnetically heated rotary kilns, excessively high chloride content in the material can also cause material blockage and corrosion of the kiln walls.

[0005] In view of the above, there is an urgent need for a new process for the resource utilization of fly ash from waste incineration that can eliminate the need for high-energy-consuming fuel heating, get rid of the dependence on water washing process, generate no wastewater, and efficiently solve the problems of high-temperature chloride scale and corrosion. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a high-temperature desalination and detoxification system and method for fly ash utilization based on an electromagnetically heated rotary kiln. Employing direct electromagnetic induction heating combined with innovative processes such as "material back-mixing - steel ball cleaning" and "high-temperature filtration - rapid cooling crystallization," this system achieves complete detoxification and full resource utilization of fly ash while significantly reducing energy consumption. Furthermore, the entire process generates no industrial wastewater and has a low tail gas treatment load, making it highly valuable for industrial applications. To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows: A high-temperature desalination and detoxification utilization system for fly ash based on an electromagnetically heated rotary kiln is provided, which includes a raw material pretreatment and feeding component, an electromagnetically heated rotary kiln, a high-temperature flue gas desalination and purification component, and a detoxification product classification and circulation component. The raw material pretreatment and feeding assembly includes a raw material silo, a metering and weighing device, a mixer and a preheating control unit connected in sequence by pipelines. The raw material silo includes a fly ash silo and an auxiliary material silo, which are respectively connected to the metering and weighing device. The feed end of the electromagnetic heating rotary kiln is connected to the discharge end of the preheating control unit; the electromagnetic heating rotary kiln is filled with steel balls as grinding and heating medium. The alternating magnetic field generated by the induction coil of the electromagnetically heated rotary kiln directly acts on the metal rotary kiln shell and the heat-resistant steel balls inside the kiln, causing both to heat up simultaneously. The high-temperature shell directly heats the material adhering to the wall, while the high-temperature steel balls heat the material bed internally, significantly improving heat utilization and ensuring extremely uniform heating of the material. Electromagnetic heating can achieve rapid response by adjusting the output power, precisely controlling the kiln temperature within the optimal process window of 1000~1100℃. This avoids incomplete salt volatilization due to excessively low temperatures or material melting due to excessively high temperatures, ensuring maximum chloride volatilization efficiency without causing over-melting. The steel balls inside the kiln are not only a moving heat source but also a powerful grinding medium. During rotation, the steel balls continuously tumble and impact, playing two main roles: first, grinding and crushing, breaking up the sintered agglomerates of fly ash particles, exposing the internally encased chlorides, and accelerating their volatilization; second, mechanically scraping the wall, the scouring action of the steel balls effectively removes the initial adhesive layer formed on the kiln wall, preventing "ringing" and ensuring long-term continuous operation of the equipment. Because electromagnetically heated rotary kilns do not require fuel combustion, almost no CO2 or NO is produced inside the kiln. x The combustion exhaust gas is reduced significantly compared to traditional processes, lowering the load on subsequent dust removal and exhaust gas purification systems and providing sufficient airflow for blast cooling. Furthermore, utilizing preheated clean hot air as carrier gas for reuse in the kiln effectively improves the mass transfer environment within the kiln without significantly increasing flue gas treatment costs.

[0007] The high-temperature flue gas salt separation and purification assembly includes a high-temperature filter, an air-cooled jacketed quench tower, a bag filter, a tail gas purification tower, an induced draft fan, and a chimney connected in sequence. The air inlet of the high-temperature filter is connected to the air outlet of the electromagnetic heating rotary kiln. The high-temperature filter is a high-temperature resistant iron-chromium-aluminum metal fiber filter bag equipped with a pulse backflushing system. The air-cooled jacketed quench tower is equipped with a jacketed air inlet and a quenching medium injection inlet. The jacketed air inlet is connected to a first blower, and the quenching medium injection inlet is connected to a second blower. The outlet of the air-cooled jacketed quench tower is connected to a coarse salt collection bin, and the outlet of the bag filter is connected to a fine salt collection bin. This invention cleverly utilizes the significant difference in the physical states of the main components (aluminosilicate matrix) and impurity components (chlorides, heavy metals) in fly ash at high temperatures, achieving graded separation through precise temperature field control. In the electromagnetically heated rotary kiln and high-temperature filtration unit, the temperature is maintained above the volatilization temperature of chlorides. At this point, the fly ash matrix remains in solid particles, while the chlorides remain gaseous. Utilizing the deep filtration effect of high-temperature resistant iron-chromium-aluminum metal fiber filter bags, the solid fly ash particles carried in the flue gas are trapped on the surface of the filter bags, while the gaseous chlorides pass through the filter bags to the next stage. This step achieves complete separation of ash and salt, providing a foundation for the subsequent capture of high-purity salts. The clean flue gas passing through the high-temperature filter bags enters the air-cooled jacketed quench tower. Cold air is injected directly into the inner cylinder as the quenching medium by a blower and mixed with the high-temperature flue gas. Under the action of turbulent mixing combined with jacketed air cooling, the flue gas temperature rapidly decreases from above 800°C to below 200°C within 1 second. This process not only instantly condenses gaseous chloride salts into solid microcrystals, avoiding adhesion and blockage on the heat exchange wall, but also allows the solid salt particles after rapid cooling and crystallization to escape with the low-temperature flue gas. The gravity settling effect at the bottom of the rapid cooling and crystallization unit captures some of the agglomerated large coarse salt particles, while the precision filtration of a bag filter captures fine salt powder, thus achieving efficient recovery of salt resources.

[0008] The detoxification product grading and circulation assembly includes a multi-stage vibrating screen separator, a back-mixing belt, and a vertical conveyor. The feed end of the multi-stage vibrating screen separator is connected to the discharge port of the electromagnetically heated rotary kiln. The multi-stage vibrating screen separator is equipped with a first outlet, a second outlet, and a third outlet. The first outlet is connected to the vertical conveyor, which is used to transport the steel balls screened out to the electromagnetically heated rotary kiln. The second outlet is connected to the back-mixing belt, which is used to transport the large-particle-size detoxification products screened out to the mixer. The third outlet is connected to a finished product bin, which is used to store small-particle-size detoxification products.

[0009] Furthermore, it also includes a waste heat recovery pipeline, one end of which is connected to the clean hot air outlet of the air-cooled jacketed quench tower, and the other end of which is connected to the preheating control unit.

[0010] Furthermore, the preheating control unit is a jacketed screw feeder. The hot medium inlet of the jacketed screw feeder is connected to the waste heat recovery pipeline, and the cooling medium outlet of the jacketed screw feeder is connected to the air inlet of the electromagnetic heating rotary kiln through a pipeline.

[0011] This invention further reduces overall system energy consumption by remixing products and steel balls and utilizing the waste heat of high-temperature flue gas, building upon electromagnetic heating. Fly ash and auxiliary materials are mixed and fed into an electromagnetically heated rotary kiln for high-temperature treatment. The material collected at the outlet includes detoxified products and steel balls. Larger particles of detoxified products and steel balls, separated by a multi-stage vibrating screen separator, are returned to the kiln via an independent loop, bringing the high-temperature heat back to the reaction zone and reducing the electrical energy required for reheating the electromagnetically heated rotary kiln. At room temperature air is introduced into the jacket layer outside the tower body to cool the inner cylinder wall and absorb heat, converting it into clean hot air. This clean hot air is then introduced into the preheating control unit to dry and preheat the materials. The preheated gas (approximately 100-150°C) is distributed through a flow regulating valve in the pipeline: a portion is introduced into the electromagnetically heated rotary kiln as process carrier gas, utilizing its sensible heat and reducing the chloride partial pressure within the kiln; the other portion (excess air volume) is directly introduced into the exhaust gas purification system. This design ensures the stability of the airflow within the rotary kiln while maximizing the utilization of heat energy and gas.

[0012] The present invention also provides a method for high-temperature desalination and detoxification of fly ash using the above-mentioned fly ash high-temperature desalination and detoxification utilization system based on electromagnetic heating rotary kiln, comprising the following steps: S1: Batching and remixing: The incineration fly ash stored in the fly ash bin and the non-chlorine-containing silicon-aluminum solid waste auxiliary materials stored in the auxiliary material bin are weighed and measured by a metering device and then transported to the mixer. S2: Preheating and feeding: After the mixer mixes the materials, it conveys the materials to the preheating control unit. After the preheating control unit preheats the materials, it conveys the preheated materials to the electromagnetic heating rotary kiln. S3: High-temperature desalination and detoxification: In the electromagnetic heating rotary kiln, the cylinder of the electromagnetic heating rotary kiln and the steel balls filled in the kiln are heated by electromagnetic induction. The steel balls are used as heating elements and grinding media to treat the materials entering the kiln at high temperature. Clean hot air is continuously blown into the kiln. The clean hot air carries the high-temperature flue gas through the air outlet of the electromagnetic heating rotary kiln to the high-temperature filtration device. Meanwhile, the solid products discharged from the electromagnetic heating rotary kiln enter the multi-stage vibrating screen separator; the multi-stage vibrating screen separator separates steel balls, large-particle-size detoxified products and small-particle-size detoxified products; the steel balls are returned to the interior of the electromagnetic heating rotary kiln through a vertical conveying device, the large-particle-size detoxified products are returned to the mixer through a remixing belt, and the small-particle-size detoxified products are transported to the finished product silo. S4: High-temperature dust removal: The high-temperature filtration device filters out fly ash particles and fine particles rich in heavy metals carried in high-temperature flue gas. S5: Rapid Cooling Crystallization and Salt Separation: The first and second blowers operate, rapidly cooling the clean, high-temperature flue gas filtered by the high-temperature filtration device to below 200°C through the air-cooled jacketed rapid cooling tower. The gaseous salt substances undergo phase change and crystallize into solid particles. At the same time, the clean hot air inside the jacket of the air-cooled jacketed rapid cooling tower is blown to the jacketed screw feeder and the electromagnetic heating rotary kiln. The coarser solid particles fall directly to the outlet of the air-cooled jacketed rapid cooling tower and are collected in the coarse salt collection bin. The finer solid particles are further carried by the airflow to the bag filter, which collects the finer solid particles in the fine salt collection bin. The air-cooled jacketed quench tower rapidly reduces the temperature of the filtered flue gas from above 850℃ to below 200℃ by introducing cold air and coordinating with jacket cooling. This allows gaseous salts to avoid the bonding temperature zone and dioxin regeneration temperature zone, and rapidly crystallize into solid particles through phase change. The clean hot air recovered by the jacket of the air-cooled jacketed quench tower is returned to the preheating control unit for preheating and control. After heat exchange, it is sent as process gas to the electromagnetically heated rotary kiln. Some of the coarse salt falls into the salt recovery outlet and enters the coarse salt collection bin. The cooled salt-containing flue gas enters the bag filter unit for gas-solid separation. The separated and recovered fine salt enters the fine salt recovery bin. The high-purity (85~90%) salts obtained by the quench tower and bag filter are utilized as industrial by-product salts or industrial raw material salts.

[0013] S6: Deep purification of exhaust gas: The flue gas treated by the bag filter enters the exhaust gas purification tower to remove residual acidic gases and pollutants. The purified exhaust gas is discharged through the chimney by the induced draft fan and meets the emission standards.

[0014] The method used in this invention does not employ water washing processes throughout the entire process and does not generate wastewater; it synergistically ensures that the soluble chlorine content in the detoxification product is no higher than 2%, the dioxin content is no higher than 50 ng-TEQ / kg, and the heavy metal leaching content meets the standards; the small-particle-size detoxification product can be used as a cement admixture, concrete admixture, brick aggregate, or roadbed filler for building material utilization.

[0015] Furthermore, in step S1, the mass ratio of fly ash to auxiliary materials is 40~60:60~40.

[0016] Furthermore, in step S2, the preheating control unit preheats the material to 100~250℃. Furthermore, in step S3, the electromagnetic heating rotary kiln is heated to 1000~1100℃ by electromagnetic induction, and the residence time of the material in the electromagnetic heating rotary kiln is 60~90min by changing the kiln rotation speed and tilt angle; the rotation speed of the electromagnetic heating rotary kiln is 0.8~1.8r / min, and the tilt angle of the axis relative to the horizontal plane is 1~3°.

[0017] Furthermore, in step S4, the high-temperature filtration device operates at a temperature of 800~850℃, and the high-temperature resistant iron-chromium-aluminum metal fiber filter bag is cleaned by a pulse backflushing system.

[0018] The beneficial effects of this invention are as follows: This invention provides a high-temperature desalination and detoxification system and method for fly ash based on an electromagnetically heated rotary kiln. By electromagnetically induction heating steel balls and the kiln body, precise temperature control of fly ash is achieved under high-temperature conditions. It innovatively combines high-temperature filtration and rapid cooling crystallization processes to achieve efficient separation of gaseous chlorides and solid ash without water washing. This method can achieve complete thermal decomposition and regeneration inhibition of dioxins at 1000~1100℃, while simultaneously achieving long-term stabilization of heavy metals through lattice solidification and physical encapsulation, yielding detoxified products with building material utilization value and salts with resource utilization value. Through the synergistic design of steel ball and material remixing for sensible heat recovery, high-temperature flue gas waste heat utilization, and steel ball circulating grinding for wall cleaning, this invention not only effectively solves the problems of rotary kiln ring clogging and high energy consumption, but also significantly reduces the overall system operating energy consumption and flue gas volume, achieving the coordinated treatment of fly ash reduction, harmlessness, and resource utilization. The system has a simple process flow, stable operation, low modification and operating costs, good engineering adaptability and significant environmental and economic benefits, and therefore has broad prospects for engineering application and industrialization.

[0019] This invention employs electromagnetic induction to heat the kiln body and steel balls, directly transferring heat to the material through contact, achieving precise temperature control, high thermal efficiency, and no combustion exhaust gas. The system's flue gas volume is significantly reduced compared to traditional processes. Combined with the remixing of sensible heat from the steel balls and materials, and the utilization of waste heat from the flue gas, operating energy consumption is significantly reduced.

[0020] This invention employs a waterless, high-temperature salt separation method, innovatively combining high-temperature filtration and rapid cooling crystallization processes. It completely separates gaseous salt and solid ash at temperatures above 850℃, avoiding the generation of wastewater from the washing process. The rapid cooling technology avoids the adhesion zone, synergistically ensuring that the soluble chlorine content of the detoxification product is no higher than 2%, and the purity of the recovered salt reaches 90%, demonstrating significant potential for resource utilization.

[0021] This invention utilizes steel balls inside the kiln that combine heating and grinding functions, employing mechanical rolling to break up fly ash agglomerates and accelerate chloride volatilization; simultaneously, it continuously flushes away the initial adhesion layer on the kiln wall, and combines fly ash with auxiliary materials before entering the kiln, fundamentally solving the problem of "ringing" blockage in rotary kilns and ensuring long-term stable operation of the system.

[0022] This invention utilizes a high temperature of 1000~1100℃ to achieve complete thermal decomposition of dioxins (removal rate >95%) and inhibition of regeneration, with the dioxin content in the detoxification product not exceeding 50 ng-TEQ / kg. Heavy metals are permanently stabilized through lattice solidification and physical encapsulation, and the leaching toxicity of the detoxification product meets fly ash disposal standards. The detoxification product is mainly composed of calcium-silicon-aluminum mineral phases, possessing value for building material applications. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a high-temperature desalination and detoxification system for fly ash. Detailed Implementation

[0024] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0025] Example 1 like Figure 1 As shown, a high-temperature desalination and detoxification utilization system for fly ash based on an electromagnetically heated rotary kiln includes a raw material pretreatment and feeding assembly, an electromagnetically heated rotary kiln, a high-temperature flue gas desalination and purification assembly, and a detoxification product classification and circulation assembly. The raw material pretreatment and feeding assembly includes a raw material silo, a metering and weighing device, a mixer, and a preheating control unit connected sequentially by pipelines. The raw material silo includes a fly ash silo and an auxiliary material silo, which are respectively connected to the metering and weighing device. The auxiliary material silo stores chlorine-free silicoaluminous solid waste auxiliary materials, including one or more of fly ash, kaolin, coal gangue, blast furnace slag, aluminum ash, metallurgical slag, silicon slag, red mud, tailings, and municipal construction waste in any proportion. The feed end of the electromagnetic heating rotary kiln is connected to the discharge end of the preheating control unit; the electromagnetic heating rotary kiln is filled with steel balls as grinding and heating medium; the steel balls are made of 310S heat-resistant stainless steel. The high-temperature flue gas desalination and purification assembly includes a high-temperature filter, an air-cooled jacketed quench tower, a bag filter, a tail gas purification tower, an induced draft fan, and a chimney connected in sequence. The air inlet of the high-temperature filter is connected to the air outlet of the electromagnetically heated rotary kiln. The high-temperature filter is a high-temperature resistant iron-chromium-aluminum metal fiber filter bag equipped with a pulse backflushing system. In practice, an external insulation layer is also provided. The air-cooled jacketed quench tower is equipped with a jacketed air inlet and a quenching medium injection inlet. The jacketed air inlet is connected to a first blower, and the quenching medium injection inlet is connected to a second blower. The outlet of the air-cooled jacketed quench tower is connected to a coarse salt collection bin, and the outlet of the bag filter is connected to a fine salt collection bin. The detoxification product grading and circulation assembly includes a multi-stage vibrating screen separator, a back-mixing belt, and a vertical conveyor. The feed end of the multi-stage vibrating screen separator is connected to the discharge port of the electromagnetically heated rotary kiln. The multi-stage vibrating screen separator is equipped with a first outlet, a second outlet, and a third outlet. The first outlet is connected to the vertical conveyor, which is used to transport the steel balls screened out to the electromagnetically heated rotary kiln. In specific implementations, the vertical conveyor is a bucket elevator. The second outlet is connected to the back-mixing belt, which is used to transport the large-particle-size detoxification products screened out to the mixer. The third outlet is connected to a finished product bin, which is used to store small-particle-size detoxification products.

[0026] It also includes a waste heat recovery pipeline, one end of which is connected to the clean hot air outlet of the air-cooled jacketed quench tower, and the other end of which is connected to the preheating control unit.

[0027] The preheating control unit is a jacketed screw feeder. The hot medium inlet of the jacketed screw feeder is connected to the waste heat recovery pipeline, and the cooling medium outlet of the jacketed screw feeder is connected to the air inlet of the electromagnetic heating rotary kiln through a pipeline.

[0028] This invention utilizes the high-temperature field created by an electromagnetically heated rotary kiln and specific process conditions to achieve efficient separation of chloride salts and deep removal of pollutants from fly ash through the synergistic effect of physical phase change and chemical reaction. The specific mechanism is as follows: 1. High-Temperature Vaporization of Soluble Chlorides: Separation is achieved by utilizing the significant differences in melting point and volatility characteristics between chlorides (NaCl melting point 801℃, KCl melting point 770℃) and the calcium-silicon-aluminum matrix of fly ash. Under electromagnetic heating at 1000~1100℃, the low-melting-point chlorides in the fly ash undergo a phase transition, melting from a solid to a liquid state. Under saturated vapor pressure, they volatilize and escape from the pores of the fly ash matrix into the gas phase. This physical phase transition achieves the initial dissociation of chlorides from the fly ash matrix, creating the prerequisite for subsequent gas-solid separation.

[0029] 2. Heavy metal stabilization: During the high-temperature treatment process, the heavy metals in fly ash undergo solid-phase or liquid-phase reactions with mineral components such as SiO2, Al2O3, and CaO under high temperature to form dense and thermodynamically stable silicate, aluminate, or spinel phases, in which the heavy metals enter the mineral lattice. At the same time, sintering densification reduces porosity and specific surface area, and the heavy metals are physically encapsulated in the dense sintered body, inhibiting the migration and dissolution of heavy metals, thereby achieving long-term stabilization and solidification.

[0030] 3. Complete Degradation of Dioxins: The ultra-high temperature environment above 1000℃ and sufficient residence time in the electromagnetic kiln are sufficient to completely destroy the benzene ring structure and C-Cl bond of dioxins, achieving complete degradation at the source. At the same time, the process utilizes temperature control to allow the flue gas to quickly pass through the "de novo synthesis" temperature zone of 250-450℃, blocking the regeneration reaction of dioxins and ensuring safe emissions.

[0031] Example 2 The system described in Example 1 is used for high-temperature desalination and detoxification of fly ash, specifically including the following steps: S1: Batching and Remixing: The incineration fly ash stored in the fly ash bin and the non-chlorine-containing silicon-aluminum solid waste auxiliary materials stored in the auxiliary material bin are weighed and metered by a metering device and then transported to the mixer; the mass ratio of fly ash to auxiliary materials is 40:60.

[0032] S2: Preheating and feeding: After the mixer mixes the materials, it conveys the materials to the preheating control unit, which preheats the materials to 100°C and then conveys the preheated materials to the electromagnetic heating rotary kiln. S3: High-temperature desalination and detoxification: In the electromagnetic heating rotary kiln, the cylinder of the rotary kiln and the steel balls filled in the kiln are electromagnetically induction heated to a temperature of 1000℃. The kiln rotation speed is 1.8r / min, and the inclination angle of the axis relative to the horizontal plane is 3°. The residence time of the material in the electromagnetic heating rotary kiln is 60min. The steel balls are used as heating and grinding media to treat the material entering the kiln at high temperature. Clean hot air is continuously blown into the kiln. The clean hot air carries the high-temperature flue gas through the outlet of the electromagnetic heating rotary kiln to the high-temperature filtration device. Simultaneously, the solid products discharged from the electromagnetically heated rotary kiln enter a multi-stage vibrating screen separator; the multi-stage vibrating screen separator separates steel balls, large-particle-size detoxified products, and small-particle-size detoxified products; the steel balls are returned to the interior of the electromagnetically heated rotary kiln via a vertical conveyor, the large-particle-size detoxified products are returned to the mixer via a remixing belt, and the small-particle-size detoxified products are transported to the finished product silo; the soluble chlorine content in the separated small-particle-size detoxified products is no higher than 2%, the dioxin content is no higher than 50 ng-TEQ / kg, and the heavy metal leaching content meets the standards. S4: High-temperature dust removal: The high-temperature filtration device filters out fly ash particles and fine particles rich in heavy metals carried in high-temperature flue gas at temperatures above 800℃; the metal filter bags are cleaned using a pulse back-flushing system to achieve a 90% dust collection rate. S5: Rapid Cooling Crystallization and Salt Separation: The first and second blowers operate, rapidly cooling the clean, high-temperature flue gas (above 800°C) filtered by the high-temperature filtration device to below 200°C through a jacketed rapid cooling tower. Gaseous salts undergo phase change and crystallize into solid particles. Simultaneously, clean hot air from the jacket of the jacketed rapid cooling tower is blown towards the jacketed screw feeder and the electromagnetically heated rotary kiln. Coarser solid particles fall directly to the outlet of the jacketed rapid cooling tower and are collected in the coarse salt collection bin. Finer solid particles are further carried by the airflow to the bag filter, which collects them in the fine salt collection bin. The separated high-purity (85%) salt is utilized as industrial by-product salt or industrial raw material salt. S6: Deep purification of exhaust gas: The flue gas treated by the bag filter enters the exhaust gas purification tower to remove residual acidic gases and pollutants. The purified exhaust gas is discharged through the chimney by the induced draft fan and meets the emission standards.

[0033] Example 3 The system described in Example 1 is used for high-temperature desalination and detoxification of fly ash, specifically including the following steps: S1: Batching and Remixing: The incineration fly ash stored in the fly ash bin and the non-chlorine-containing silicon-aluminum solid waste auxiliary materials stored in the auxiliary material bin are weighed and metered by a metering device and then transported to the mixer; the mass ratio of fly ash to auxiliary materials is 50:50.

[0034] S2: Preheating and feeding: After the mixer mixes the materials, it conveys the materials to the preheating control unit, which preheats the materials to 175°C and then conveys the preheated materials to the electromagnetic heating rotary kiln. S3: High-temperature desalination and detoxification: In the electromagnetic heating rotary kiln, the cylinder of the rotary kiln and the steel balls filled in the kiln are electromagnetically induction heated to a temperature of 1050℃. The kiln rotation speed is 1.3r / min, and the inclination angle of the axis relative to the horizontal plane is 2°. The residence time of the material in the electromagnetic heating rotary kiln is 75min. The steel balls are used as heating and grinding media to treat the material entering the kiln at high temperature. Clean hot air is continuously blown into the kiln. The clean hot air carries the high-temperature flue gas through the outlet of the electromagnetic heating rotary kiln to the high-temperature filtration device. Simultaneously, the solid products discharged from the electromagnetically heated rotary kiln enter a multi-stage vibrating screen separator; the multi-stage vibrating screen separator separates steel balls, large-particle-size detoxified products, and small-particle-size detoxified products; the steel balls are returned to the interior of the electromagnetically heated rotary kiln via a vertical conveyor, the large-particle-size detoxified products are returned to the mixer via a remixing belt, and the small-particle-size detoxified products are transported to the finished product silo; the soluble chlorine content in the separated small-particle-size detoxified products is no higher than 2%, the dioxin content is no higher than 50 ng-TEQ / kg, and the heavy metal leaching content meets the standards. S4: High-temperature dust removal: The high-temperature filtration device filters out fly ash particles and fine particles rich in heavy metals carried in high-temperature flue gas at temperatures above 825℃; the metal filter bags are cleaned using a pulse back-flushing system to achieve a dust collection rate of 87%. S5: Rapid Cooling Crystallization and Salt Separation: The first and second blowers operate, rapidly cooling the clean, high-temperature flue gas (above 825°C) filtered by the high-temperature filtration device to below 200°C through a jacketed rapid cooling tower. Gaseous salts undergo phase change and crystallize into solid particles. Simultaneously, clean hot air from the jacket of the jacketed rapid cooling tower is blown towards the jacketed screw feeder and the electromagnetically heated rotary kiln. Coarser solid particles fall directly to the outlet of the jacketed rapid cooling tower and are collected in the coarse salt collection bin. Finer solid particles are further carried by the airflow to the bag filter, which collects them in the fine salt collection bin. The separated high-purity (88%) salt is utilized as industrial by-product salt or industrial raw material salt. S6: Deep purification of exhaust gas: The flue gas treated by the bag filter enters the exhaust gas purification tower to remove residual acidic gases and pollutants. The purified exhaust gas is discharged through the chimney by the induced draft fan and meets the emission standards.

[0035] Example 4 The system described in Example 1 is used for high-temperature desalination and detoxification of fly ash, specifically including the following steps: S1: Batching and Remixing: The incineration fly ash stored in the fly ash bin and the non-chlorine-containing silicon-aluminum solid waste auxiliary materials stored in the auxiliary material bin are weighed and metered by a metering device and then transported to the mixer; the mass ratio of fly ash to auxiliary materials is 60:40.

[0036] S2: Preheating and feeding: After the mixer mixes the materials, it conveys the materials to the preheating control unit, which preheats the materials to 250°C and then conveys the preheated materials to the electromagnetic heating rotary kiln. S3: High-temperature desalination and detoxification: In the electromagnetic heating rotary kiln, the cylinder of the rotary kiln and the steel balls filled in the kiln are electromagnetically induction heated to a temperature of 1100℃. The kiln rotation speed is 0.8r / min, and the inclination angle of the axis relative to the horizontal plane is 1°. The residence time of the material in the electromagnetic heating rotary kiln is 90min. The steel balls are used as heating and grinding media to treat the material entering the kiln at high temperature. Clean hot air is continuously blown into the kiln. The clean hot air carries the high-temperature flue gas through the outlet of the electromagnetic heating rotary kiln to the high-temperature filtration device. Simultaneously, the solid products discharged from the electromagnetically heated rotary kiln enter a multi-stage vibrating screen separator; the multi-stage vibrating screen separator separates steel balls, large-particle-size detoxified products, and small-particle-size detoxified products; the steel balls are returned to the interior of the electromagnetically heated rotary kiln via a vertical conveyor, the large-particle-size detoxified products are returned to the mixer via a remixing belt, and the small-particle-size detoxified products are transported to the finished product silo; the soluble chlorine content in the separated small-particle-size detoxified products is no higher than 2%, the dioxin content is no higher than 50 ng-TEQ / kg, and the heavy metal leaching content meets the standards. S4: High-temperature dust removal: The high-temperature filtration device filters out fly ash particles and fine particles rich in heavy metals carried in high-temperature flue gas at temperatures above 850℃; the metal filter bags are cleaned using a pulse back-flushing system to achieve a dust collection rate of 85%. S5: Rapid Cooling Crystallization and Salt Separation: The first and second blowers operate, rapidly cooling the clean, high-temperature flue gas (above 850°C) filtered by the high-temperature filtration device to below 200°C through a jacketed rapid cooling tower. Gaseous salts undergo phase change and crystallize into solid particles. Simultaneously, clean hot air from the jacket of the jacketed rapid cooling tower is blown towards the jacketed screw feeder and the electromagnetically heated rotary kiln. Coarser solid particles fall directly to the outlet of the jacketed rapid cooling tower and are collected in the coarse salt collection bin. Finer solid particles are further carried by the airflow to the bag filter, which collects them in the fine salt collection bin. The separated high-purity (90%) salt is utilized as industrial by-product salt or industrial raw material salt. S6: Deep purification of exhaust gas: The flue gas treated by the bag filter enters the exhaust gas purification tower to remove residual acidic gases and pollutants. The purified exhaust gas is discharged through the chimney by the induced draft fan and meets the emission standards.

Claims

1. A high-temperature desalination and detoxification utilization system for fly ash based on an electromagnetically heated rotary kiln, characterized in that, This includes raw material pretreatment and feeding components, electromagnetic heating rotary kiln, high-temperature flue gas desalination and purification components, and detoxification product classification and circulation components. The raw material pretreatment and feeding assembly includes a raw material silo, a metering and weighing device, a mixer and a preheating control unit connected in sequence by pipelines. The raw material silo includes a fly ash silo and an auxiliary material silo, which are respectively connected to the metering and weighing device. The feed end of the electromagnetic heating rotary kiln is connected to the discharge end of the preheating control unit; the electromagnetic heating rotary kiln is filled with steel balls as grinding and heating medium. The high-temperature flue gas desalination and purification assembly includes a high-temperature filter, an air-cooled jacketed quench tower, a bag filter, a tail gas purification tower, an induced draft fan, and a chimney connected in sequence. The air inlet of the high-temperature filter is connected to the air outlet of the electromagnetically heated rotary kiln. The high-temperature filter is a high-temperature resistant iron-chromium-aluminum metal fiber filter bag equipped with a pulse backflushing system. The air-cooled jacketed quench tower is equipped with a jacketed air inlet and a quenching medium injection inlet. The jacketed air inlet is connected to a first blower, and the quenching medium injection inlet is connected to a second blower. The outlet of the air-cooled jacketed quench tower is connected to a coarse salt collection bin, and the outlet of the bag filter is connected to a fine salt collection bin. The detoxification product grading and circulation assembly includes a multi-stage vibrating screen separator, a back-mixing belt, and a vertical conveyor. The feed end of the multi-stage vibrating screen separator is connected to the discharge port of the electromagnetically heated rotary kiln. The multi-stage vibrating screen separator is provided with a first outlet, a second outlet, and a third outlet. The first outlet is connected to the vertical conveyor, which is used to transport the steel balls screened out to the electromagnetically heated rotary kiln. The second outlet is connected to the back-mixing belt, which is used to transport the large-particle-size detoxification products screened out to the mixer. The third outlet is connected to a finished product bin, which is used to store small-particle-size detoxification products.

2. The fly ash high-temperature desalination and detoxification utilization system based on an electromagnetically heated rotary kiln according to claim 1, characterized in that, It also includes a waste heat recovery pipeline, one end of which is connected to the clean hot air outlet of the air-cooled jacketed quench tower, and the other end of which is connected to the preheating control unit.

3. The high-temperature desalination and detoxification system for fly ash based on an electromagnetically heated rotary kiln according to claim 2, characterized in that, The preheating control unit is a jacketed screw feeder. The hot medium inlet of the jacketed screw feeder is connected to the waste heat recovery pipeline, and the cooling medium outlet of the jacketed screw feeder is connected to the air inlet of the electromagnetic heating rotary kiln through a pipeline.

4. A method for high-temperature desalination and detoxification of fly ash using the fly ash high-temperature desalination and detoxification utilization system based on an electromagnetically heated rotary kiln as described in claim 3, characterized in that, Includes the following steps: S1: Batching and remixing: The incineration fly ash stored in the fly ash bin and the non-chlorine-containing silicon-aluminum solid waste auxiliary materials stored in the auxiliary material bin are weighed and measured by a metering device and then transported to the mixer. S2: Preheating and feeding: After the mixer mixes the materials, it conveys the materials to the preheating control unit. After the preheating control unit preheats the materials, it conveys the preheated materials to the electromagnetic heating rotary kiln. S3: High-temperature desalination and detoxification: In the electromagnetic heating rotary kiln, the cylinder of the electromagnetic heating rotary kiln and the steel balls filled in the kiln are heated by electromagnetic induction. The steel balls are used as heating elements and grinding media to treat the materials entering the kiln at high temperature. Clean hot air is continuously blown into the kiln. The clean hot air carries the high-temperature flue gas through the air outlet of the electromagnetic heating rotary kiln to the high-temperature filtration device. Meanwhile, the solid products discharged from the electromagnetic heating rotary kiln enter the multi-stage vibrating screen separator; the multi-stage vibrating screen separator separates steel balls, large-particle-size detoxified products and small-particle-size detoxified products; the steel balls are returned to the interior of the electromagnetic heating rotary kiln through a vertical conveying device, the large-particle-size detoxified products are returned to the mixer through a remixing belt, and the small-particle-size detoxified products are transported to the finished product silo. S4: High-temperature dust removal: The high-temperature filtration device filters out fly ash particles and fine particles rich in heavy metals carried in high-temperature flue gas. S5: Rapid Cooling Crystallization and Salt Separation: The first and second blowers operate, rapidly cooling the clean, high-temperature flue gas filtered by the high-temperature filtration device to below 200°C through the air-cooled jacketed rapid cooling tower. The gaseous salt substances undergo phase change and crystallize into solid particles. At the same time, the clean hot air inside the jacket of the air-cooled jacketed rapid cooling tower is blown to the jacketed screw feeder and the electromagnetic heating rotary kiln. The coarser solid particles fall directly to the outlet of the air-cooled jacketed rapid cooling tower and are collected in the coarse salt collection bin. The finer solid particles are further carried by the airflow to the bag filter, which collects the finer solid particles in the fine salt collection bin. S6: Deep purification of exhaust gas: The flue gas treated by the bag filter enters the exhaust gas purification tower to remove residual acidic gases and pollutants. The purified exhaust gas is discharged through the chimney by the induced draft fan and meets the emission standards.

5. The method according to claim 4, characterized in that, In step S1, the mass ratio of fly ash to auxiliary materials is 40~60:60~40.

6. The method according to claim 5, characterized in that, In step S2, the preheating control unit preheats the material to 100~250℃.

7. The method according to claim 4, characterized in that, In step S3, the electromagnetic heating rotary kiln is heated to 1000~1100℃ by electromagnetic induction. The residence time of the material in the electromagnetic heating rotary kiln is 60~90min by changing the kiln rotation speed and tilt angle. The rotation speed of the electromagnetic heating rotary kiln is 0.8~1.8r / min, and the tilt angle of the axis relative to the horizontal plane is 1~3°.

8. The method according to claim 4, characterized in that, In step S4, the high-temperature filtration device operates at a temperature of 800~850℃, and the high-temperature resistant iron-chromium-aluminum metal fiber filter bag is cleaned by a pulse backflushing system.

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